package com.example.day16;

/**
 * @author Lenovo
 */
public class MapDemo02 {
    public static void main(String[] args) {
        HashMap<String, Integer> map = new HashMap<Object, Integer>();
map.put("张三", 18);
map.put("李四", 19);
map.put("王五", 20);
        System.out.println(map.size);
        System.out.println(map);
    }
}
